Acid green indolyldiphenylmethane dyestuff



Patented May 28, 1940 usu'reo STATES PATENT oFF oE ACID GREEN INDOLYLDIPHENYLMETHAN E DYE STUFF Paul Wolff and Emil Beniers, Frankfort-on-the- Main, Germany, assignors to General Aniline & Film Corporation, a corporation of Delaware No Drawing. Application May 13; 1938, Serial No. 207,788. In Germany May 24, 1937 3 Claims.

SOzOH H I wherein R represents N-alkyl-indole radical bound in its ,B-position to the methane carbon atom and containing in its alpha-position a phenyl radical.

We have found that acid green indolyldiphenylmethane dyestuffs having valuable properties are obtained by condensing a l'-halogenbenzophenone-2-sulfonic acid with an indole compound which is unsubstituted in beta-position and contains in oc-DOSitlOlfl a substituent, such as for instance, a phenyl group or a substituted phenyl group, a methyl group or an ethyl group, sulfonating the condensation product and causing the halogen atom standing in 4-position to the methane carbon atom to react with a primary aromatic amine containing in para-position to the amino group an alkoxy group, for instance, a methoxy group or an ethoxy group.

The practicability of the present process could not be foreseen since in the benzophenone compounds used as starting materials there is in ortho-position to the keto group a sulfonic acid group which might have a detrimental effect on the condensation to the indolyldiphenylmethane dyestuifs. In comparison with the known dyestuffs, the dyestuffs obtainable according to the present invention are distinguished by the fact that they yield more even and more beautiful dyeings.

The following examples serve to illustrate the invention, but they are not intended to limit it thereto: I

(1) 1 mol. of sodium-4'-chlorobenzophenone- 2-sulfonate (obtainable by condensing, according to Friedel Crafts reaction, ortho-sulfobenzoic anhydride with chlorobenzene in the presence of aluminium chloride) is condensed with 1 mol of l-methyl-2-phenylindole by heating for 15 to 20 hours at about C. to C. in an excess of chlorosulfonic acid whereby simultaneous sulfonation to the disulfonic acid occurs. The condensation product is precipitated by pouring the whole into water and is washed until free from acid, dried and heated together with an excess of paraphenetidine at C. for several hours, for instance, 2, to 3 hours, after elimination of the excess of paraphenetidine by means of dilute hydrochloric acid a, dyestuff is thus obtained which, in the form of its sodium salt dyes wool and silk bluish-green tints of very good fastness to light. The dyestuif probably has the following constitution:

e OnHrO-O-HN-OCQ-SOzONa OH: I

CH2.CH.(CHB)2 We claim: 1. The compounds of the general formula:

SOzOH R alkyLO-GHN-O-(EGSONNa wherein R represents an N-alkyl indole radical bound in its fi-position to the methane carbon atom and containing in its a-DOSitiOII a phenyl radical, said compounds being acid dyestufis yielding greenish tints of good fastness properties.

2.-The compound of the formula:

light.

silk bluish-green tints of very good fastness to 3. The compound of the formula:

SOzOH said compound being a dyestuff dyeing Wool and silk green tints of very good fastness to light.

PAUL WOLFF. 15 EMIL BENIERS. 

